Flexible endoscopy procedures such as colonoscopies are important for diagnostic and therapeutic treatment of colon cancer. Robotic endoscope designs can potentially improve the ability of physicians to position the endoscope, decrease the chance of perforation of the colon, and automate functions so that procedures are easier to complete with a single person. Most commercial endoscopes have a simple bending tip that is driven with Bowden cables down the endoscope body. Automating these systems can be difficult due to the reaction forces and frictional forces generated by tension on the Bowden cables. For these reasons, developing positioning or force output controllers for long cable drive systems and tendon drives is still an ongoing field of research. Several techniques for robotically actuating the bending tip of an endoscope to avoid the use of long control cables have also been developed including using electric motors, shape memory alloys, pneumatics, and other combined techniques.
When a colonoscopy is conducted, it is sometimes difficult to maneuver the endoscope to the end of the colon at the cecum due to the shape of the colon, resulting in incomplete colonoscopies. Some methods that could help improve this process include the use of a crawling system or a double-balloon actuation system to move the endoscope down the colon. These strategies require actively grabbing the walls of the colon and could potentially cause abrasion. Snake-like robot designs have also been considered for this application. While snake-like robotic endoscopes use rigid motorized joints, continuum bending robots have the advantage that they can complete relatively large 180 degree radius bends with a single actuator without producing many discrete corners. For the same number of actuators, a continuum design can also be longer allowing the whole length of the endoscope to be populated with bending segments and not just the tip.
Some continuum endoscope designs have multiple bending points along the length that are driven by several sets of Bowden cables with actuators located at the end. Because of the large number of cables in multi-bend designs, the endoscope becomes thicker the further away from the tip. Follow-the-leader mechanical designs use a single set of cables to create several bends along the length as the endoscope is advanced. These designs can be used to avoid colon walls thereby minimizing abrasion. However, these multi-bend and follow-the-leader designs cannot readily increase the number of bending segments and require complex drive systems at the proximal end.